AB0410 OBESITY AND ADIPOSE TISSUE CYTOKINES IN RHEUMATOID ARTRHITIS: DOES THE ROUTE OF ADMINISTRATION OF THE IL6 INHIBITORS MATTER?
Authors: M. Novella-Navarro, F. Genre Romero, A. Martínez-Feito, V. Pulito-Cueto, I. Monjo, D. Peiteado, M. A. González-Gay, C. Plasencia, A. Balsa
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Obesity has been associated with the response to biologic disease modifying anti-rheumatic drugs (bDMARDs). Obese patients have lower response to anti-TNF drugs than to other cytokine-targeted drugs, such as anti-IL6<sup>[1]</sup>. IL6 receptor inhibition is effective in the treatment of rheumatoid arthritis (RA), and there are two ways of administration: intravenous (IV) weight-adjusted tocilizumab and subcutaneous (SC) fixed-dose tocilizumab or sarilumab. However, evidence regarding the influence of body mass index (BMI) and these different routes of administration is still scarce. <h3>Objectives</h3> To analyze the role of BMI in the clinical response to antiIL6 therapy in its different routes of administration in patients with RA. To perform an in-depth analysis of the pathophysiology of obesity by assessing serum adipokine levels and their potential changes according to treatment. <h3>Methods</h3> This study involved 65 patients with RA starting IV tocilizumab at 8mg/kg every 4 weeks or SC antiIL6: tocilizumab 162mg/week or sarilumab 200mg/14days. Demographic and clinical characteristics before antiIL6 initiation (age, sex, smoking habit, age at diagnosis, concomitant and previous treatments and BMI) were collected. Laboratory parameters such as rheumatoid factor and anti-citrullinated peptide antibody were also assessed. Adipokine serum levels (leptin and adiponectin) were measured at baseline and after 6 months (6M) of treatment. Clinical response to treatment was assessed by Clinical Disease Activity Index (CDAI) 6M after initiation of the bDMARD. Differences between variables were assessed using the X2 test and Mann-Whitney test. Correlations between BMI, adipokines and other quantitative variables were assessed using the Pearson or Spearman coefficients. P-values &lt;0.05 were considered statistically significant. <h3>Results</h3> Forty seven patients started IV antiIL6 (72.3%) and 18 SC (27.7%). Thirty six (55.4%) achieved low disease activity (LDA)/remission by CDAI: 24 patients from the IV group (51.4%) and 12 (66.7%) from the SC group without significant differences (p=0.19). No differences between BMI or serum adipokine levels were associated with the achievement of LDA/remission when patients were stratified according to the route of antiIL6 administration. Leptin levels in both groups (SC and IV) were very similar at baseline and 6M and regarding changes on adipokine profile between baseline and 6M, we observed a decrease in leptin and an increase in adiponectin levels both in SC and IV (Table 1). BMI showed a significant positive correlation with leptin, overall and stratifying by route of administration, both at baseline and 6M. Adiponectin did not show a significant correlation with BMI. <h3>Conclusion</h3> Obesity and serum adipokines did not show association with the achievement of LDA/remission in patients treated with antiIL6 regardless the route of administration. Furthermore, IV and SC treatments could be used both in obese and normal-weight RA patients expecting the same efficacy. <h3>Reference</h3> [1]Novella-Navarro et al. Obesity and response to biological therapy in rheumatoid arthritis: the role of body mass index and adipose tissue cytokines. Clin Exp Rheumatol. 2022 Sep;40(9):1726-1732. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.